The cultivar, breeded at Hillier Nursery at the end of the last century, shall be named not as C. ternata, correct is Choisya x dewitteana, the recommended common name is starleaf. SCHROEDER (yearbook of the Deutsche Denrologische Gesellschaft) pointed out, that this cultivar tolerates much more frost than Choisya ternata - temperatures below -20°C caused no damage, even without any sheltering methods.
Beside that, I can recommend this plant for its extremly elegant leaves and even more for the widespreading scent of the flowers, which appear in spring and - little less - in autumn.
Another variety from the same breeder (Peter Moore) is said to be even better: ´White Dazzler´ is more compact than ´Aztec Pearl´, but I have not tested it yet.